A liquid crystal panel included in a liquid crystal display device such as a television does not emit light, and thus a backlight device is required as a separate lighting device. The backlight device is arranged behind the liquid crystal panel (i.e., on a side opposite from a display surface side). It includes a metal chassis having an opening on a liquid crystal panel side and a plurality of lamps (e.g., cold cathode tubes).
To make the liquid crystal display device thinner and lighter, each component of the liquid crystal panel and the backlight device has been made thinner and lighter. The reduction in thickness and weight of the components decreases strength of the components and accordingly lowers durability or display quality of the liquid crystal display device. To suppress the strength decrease of the components due to the weight reduction of the liquid crystal display device, the configuration as disclosed in Patent Document 1 has been known.
In the liquid crystal display device disclosed in Patent Document 1, the liquid crystal panel is sandwiched between the panel fixing fitting and the panel holder. A first stopper holds the panel fixing fitting and a chassis so as to connect them together. The panel holder is formed of plastic and in a frame and ribs are extended therefrom in the thickness direction so as to be parallel to each other. Accordingly, since the panel holder, which has been made of metal, is made of plastic, the liquid crystal display device is reduced in weight, and the ribs are extended in the thickness direction of the panel holder to suppress its strength decrease.
[Patent Document] Japanese Unexamined Patent Publication No. 2006-235128
(Problem to be Solved by the Invention)
To make the liquid crystal display device thinner, it is effective to make a chassis provided in the backlight device thinner. The chassis is generally formed of a plate member and comprised of a bottom plate and an outer rim that extends upright from a periphery of the bottom plate. To make the chassis thinner, a height from the bottom plate to an upper end of the outer rim of the chassis is required to be small. The outer rim of the chassis has a function for maintaining strength of the whole chassis. Therefore, if the height of the outer rim is small, the strength of the outer rim itself is decreased and a force for suppressing distortion of the chassis may become insufficient. If a part of the chassis gets distorted, the gaps between each cold cathode tube accommodated in the chassis and the chassis become varied. This may vary the amount of light emission from each cold cathode tube and this may lower display quality of the liquid crystal display device.